Grant-in-Aid for Scientific Research (B).
|Research Institution||Hokkaido University,|
FUJITA Mutsuhiro Hokkaido University, Faculty of Engineering, Professor, 工学部, 教授 (80001139)
TACHIBANA Harukuni Hokkaido University, Faculty of Engineering, Assistant Researcher, 工学部, 助手 (90002021)
HASEGAWA Kazuyoshi Hokkaido University, Faculty of Engineering, Assistant Researcher, 工学部, 助手 (70001328)
BANSYOU Isao Hakodate College of Tecnology, Professor, 土木工学科, 教授 (90041889)
|Project Fiscal Year
1991 – 1993
Completed(Fiscal Year 1993)
|Budget Amount *help
¥7,100,000 (Direct Cost : ¥7,100,000)
Fiscal Year 1993 : ¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1992 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1991 : ¥5,200,000 (Direct Cost : ¥5,200,000)
|Keywords||Storage Function Model / Stochastic Response / Random Differential Equation / Random Function / Golf Course / Unsaturated Flow / Water Quality / Turbidity / 貯留関数法 / 確率応答 / 確率微分方程式 / 不規則関数 / ゴルフ場 / 不飽和浸透流 / 水質 / 濁度 / 表面流 / サクション / 斜面流出 / 流出量の確率応答 / 表面舎 / 到達時間 / 土砂流出 / 植生 / 沈砂池 / 暗渠|
Recently, many local governments impose severe restrictions on constructing new golf course because they cause destruction of environment. For example, local governments set the upper limit of total number of golf course and its total area within their territory. However, it is difficult to point out scientific justification of these regulations. The main aim of this research provides methods how to evaluate effects of the construction of golf course on regional hydrological phenomena This research consists of two parts.
(1) Field observation
It is very important to observe hydrological phenomena before and after the construction. We have measured rainfall, discharge, turbidity and water quality at the construction site of new golf course from 1991 t0 1993. The construction of this golf course began in 1992 and is expected to provide service in 1995. It is too early to conclude effects of this golf course on runoff characteristics.
(2) Theoretical approach to detect the change of runoff c
-Stochastic response of storage function model-
It is very difficult to evaluate change of runoff characteristics It is well known that all observed data have always some error. Even if hydrograph before and after the construction of golf course shows some change, we have to decide this change is real one or within error. However, it is hard to estimate the range of error. This problem will be solved if we provide the confidence level of estimated discharge. We must drive the probability density function of discharge to obtain its confidence level. On the other hand, the relationship between storage and discharge is a direct method to detect the change of runoff mechanism. It is considered that stochastic response of storage model will provide the solution for above problem.
All real hydrologic processes are more or less stochastic. While the dynamics for the runoff process are described by differential equations, strictly speaking, runoff phenomena are best expressed by stochastic differential equations. Stochastic equations are grouped into three classes :
1.Initial conditions are described as stochastic or probability.
2.The parameters included in differential equations are random variables.
3.Forcing terms are random variables.
This research focuses on the last class as first step although real runoff phenomena include all three classes. First four central moments of discharge are obtained theoretically. It is possible to estimate the probability density function of discharge based on obtained first four central moments. It is concluded that the probability density function of discharge is approximated by Gamma distribution or log-normal distribution. Less